diff --git a/modules/nix-version-diff.nix b/modules/nix-version-diff.nix
new file mode 100644
index 0000000..6142216
--- /dev/null
+++ b/modules/nix-version-diff.nix
@@ -0,0 +1,12 @@
+{
+  pkgs,
+  lib,
+  ...
+}: {
+  config.system.activationScripts.report-changes = ''
+    PATH=$PATH:${lib.makeBinPath (with pkgs; [nvd nix])}
+    nvd diff $(ls -dv /nix/var/nix/profiles/system-*-link | tail -2)
+  '';
+
+  home.home.packages = [pkgs.nvd];
+}